Keywan Karimi ran into trouble with Iran's powerful Revolutionary Guards over a documentary he shot called "Writing on the City" about graffiti in the capital Tehran.

He spent 15 days in solitary confinement in 2013 and was accused of making "propaganda against the regime" and "insulting religious values".

But since then, the young avant-garde filmmaker told AFP, several other "ridiculous" charges have been added including drinking alcohol, having extramarital affairs and making pornography.

"All I was doing was filming what was being written on the walls of Tehran," said the 33-year-old, who comes from the country's Kurdish minority.